Participants in this group will receive conventional ankle interventions including ankle strength training and balance training. All treatments target the affected lower extremity for 40 minutes per session, once per day, 3 days per week for 6 weeks.

Participants in this group will be asked to perform conventional ankle training and hip strength training. The conventional ankle training routine for this group will have the same movements as the control group, but the volume of training will be half that of the control group, and the duration of training will be 20 min/session. Hip strength training will consist of elastic band resistance exercises, forward step-up and lateral step-up for 20 min/session. All treatments target the affected lower extremity for 40 minutes per session, once per day, 3 days per week for 6 weeks.

Participants in this group will be asked to perform conventional ankle training and neuromuscular electrical stimulation. The conventional ankle training routine for this group will have the same movements as the control group, but the volume of training will be half that of the control group, and the duration of training will be 20 min/session. Neuromuscular electrical stimulation aims to stimulate the gluteus maximus and gluteus mediums muscles of the affected lower limb. The researcher chose the "Neuromuscular Electrical Stimulation 1" mode for the treatment prescription (this prescription can output a variety of waveforms with frequencies varying continuously from 1 to 100 Hz to stimulate the target muscles alternately, effectively preventing muscle fatigue caused by a single stimulation) and set the stimulation time to 20 min per session. All treatments target the affected lower extremity for 40 minutes per session, once per day, 3 days per week for 6 weeks.

The program included ankle elastic band resistance training and balance training, in which the elastic band resistance training required subjects to complete resistance training in ankle plantarflexion, dorsiflexion, inversion and eversion directions with the help of elastic bands; and the balance training required subjects to complete the movements of standing with eyes open, standing with eyes closed, and throwing and catching the ball on flat ground and BOSU ball.

Using the CAIT score reflects the participant's subjective level of perceived stability of the ankle joint. The questionnaire contains 9 questions related to ankle function, mainly about ankle stability, pain and ankle sprains during daily activities, such as walking, running, descending stairs, and standing on one or two legs, with scores ranging from 0 to 30. The higher the score, the better the ankle stability.

The Tecnobody PK254P Balance Tester was used to perform static postural stability tests and dynamic postural stability tests to assess the subject's static and dynamic balance abilities. Static Postural Stability Test and Dynamic Postural Stability Test to assess the static and dynamic balance ability of the subjects. Static balance was measured by the pre The static balance ability was measured by the standard deviation in the forward and backward directions, the standard deviation in the left and right directions, the area of the movement ellipse and the circumference of the movement trajectory. The static balance ability was measured by the total stability index, anterior-posterior axis stability index, and left-right axis stability index.

The electromyographic signals of gluteus medius, gluteus maximus, tibialis anterior, peroneus longus and gastrocnemius were collected by Noraxon ultium wireless surface electromyography to analyze the total amount of discharges of the motor units of the target muscles when the target muscles were involved in the activity, so as to reflect the degree of activation of the motor units of the target muscles in the course of the exercise. The test index is the Root Mean Square (RMS) of the target muscles before and after the landing moment of the single-leg vertical jump test.